Carburetor control linkage



March 2, 1948. NUTT 2,436,397

CARBURETOR CONTROL LINKAGE Filed Feb. 1, 1945 2 Sheets-Sheet 1 March 2, 194 NUTT 2,436,897

' CARBURETOR CONTROL LINKAGE I I Filed Feb. 1, 1945 2 Sheets- Sheet 2 ELY/8712,1073 I I 155 ro Patented Mar. 2, 1948 GABB EETQR QQL IlaroldNutt, Chicago, Ill. assignor to Borg- Warner'Gorporation, Chicago; 111., a corporation of Illinois Application February- 1, 1945, Serial No. 575,642 8 Claims, (01. 74-516) The present invention relates to a control linkage for carburetors. Thearrangement is especially adapted for use to control the speed of a centrifugal clutch when the latter isv a part'of the power unit in a motor vehicle.

t e trif a c t es. f his. a acter the dictated or desirable engine speed'for initially engaging the clutch is approximately 800 M- anda om l t clutc en cm nt'me be attained with engine speeds between 1,200 R. "P. M. and 2,000 B. P. M. Usually, a small travel of the throttle pedal, for example ,5; inch, will speed up the engine from the customary idling speed of 400 RJP. M; to a speed for the full clutch enga ement. This, however, renders it difiicult to park a motor vehicle equipped witha centrifugal clutch. By the use of the present device, the same /2 inch travel of the throttle pedal will increase the engine speedonlyslightly above the initial engaging speed for the cen: trifugal clutch. This results in only enough developed torque to slowly move the car at a creeping speed for parking, [and atthe same time it gives the operator a nicety of control that.

is comparable with manual clutch operation. l kglthough it is not-required, the present control arrangement may be operatedin two steps or stages. This will permit the operator to de-, press the accelerator pedal an initial distance that is indicated by the travel of a cam with considerably less efiort than is thereafter required for the additional and full opening of the throttle. Thus the operator will be able tofeel the location during thepedal movement at Which'the initial or cam action'ceases, and since this is the point where the engine should run for parking thecar; no accurate control ofthe accelerator pedalis required.

It is contemplated that the present assembly be mounted upon the carburetor, preferably carried by the spindle or shaft that moves the butterfly throttle valve. The arrangement is such that'the valve ismoved slowly tothe open position that is desirable for the initial engagement of the centrifugal clutch during the oper-' ation of parking the car, and from that point on all the parts of the linkage areadapted tomove as a unitf-or rapidly opening the'throttle for ordinarydriving-purposes;

It is therefore the principal object of this invention to simplify the construction of'a carburetor control that is adapted for use with acentrifugally acting clutch, and to improve the ration of su h rburet r cq i t lf It s al o an. b ect. of nv ntion o arevide a controldevice-wherein-thereis initiallya very small movement 'of the throttle butterfly in the carburetor fora considerable travel of the accelerator pedal. This is highly desirable with a centrifugal clutch to permit accurate control of engine speed at relatively low R. P. M when parking a car in close quarters.

Another object of this invention is to provide a carburetor control that-is adapted to readily aifect the initial engagement ofa centrifugal clutch in a manner so that the driver is easily able to operate the vehicle at very low speeds as for example when moving the car a few inches at a time.

Another object of this invention is to provide a control linkage for a carburetor such as contemplated herein which preferably comprises a unitary assembly, the parts of which are constructed and arranged for ready mounting upon a portionof-"a carburetor, preferably the butterfly valve sp'mme; whereby thereis provided an accurate control for light torque clutch engagement when parking a motor vehicle equipped with a centrifugal clutch.

Numerous additional objects, aims and advantages of thecinvention contemplated herein will be apparent to persons skilled in the art after the construction and operation of the carburetor control linkage is understood from the within description. It is preferred to accomplish these objects and to practice theinvention in substantially the manner hereinafter fully described and'as more particularly pointed part of this specification, in which;

Fig. 1 is a side elevation of a motor vehicle power plant showing the carburetor control linkageinstalled thereon;

Fig. 2 is an enlarged side elevation of the 'control assembly, showing in dotted lines the first stage of operation;

Fig. 3 is a view similar to Fig. 2 showing the stage-0i operation for-full clutch-engagement withthe throttle opened a-substantial distance; and a Fig.4 is a sectional view taken along the plane of lined-4 on Fig.2.

The drawings are to be understood as being more or less of'a schematic character for the purpose-of disclosing a typical or preferred embodiment of the improvements contemplated herein. Inthese drawings like reference characters identify the same parts-in the difierent views;

The weights are arm 38 will swing the throttle lever counterclockwise or to the left as shown by dotted lines on fulcrumed on the usual reaction annulus. When ,7

the throttle pedal 12 is depressed by the opera-- tor the engine will speed up in the usual manner j and, as the engine speed increases, the weights ll swing radially outward to move the pressure plate toward the fly-wheel 8 thereby to engage the clutch.

Throttle pedal I2 is connected by rod 13' to an end of a first-class lever 14 which at its other end pivotally carries the adjacent end of a reciprocable accelerator rod 15 for the carburetor assembly 16 on the engine. A collar l1 pinned to rod 15 is engaged by one end of a helical spring 18 that is suitably anchored at its other end to a boss 19 on the engine, thereby to urge the rod in one direction of itsreciprocable move ment. The carburetor includes the body or fuel bowl 20 and the throat 2|, that is demountably connected to the engine intake manifold 22. Throat 2| has therein the main fuel passageway 23 which communicates with the inlet stub .24 of manifold 22. The throttle or butterfly valve 25 in passageway 23 is carried on a spindle 25 that is elongated at one end to project out of its bearing as seen in Fig. 4.

Referring articularly to Figs. 2 and 4, the throttle lever 21 comprises an arm having a split boss 28 atone end that is clamped to the extended portion-of spindle 26 by a cap screw 29, and a helical spring 21a, hooked to the swinging or free end of throttle lever 21, urges said lever to one of the limits of its swinging movement, or to the right as seen in Fig. 2. The other end of spring 21a is connected to a fixed lug 26a on the engine. Beside the throttle lever 21 there is bifurcated lever 30 having a generally U-shape and unsecured to spindle 26 so that it is free to swing on said spindle 26 upon which it is retained by a washer 3| and cotter pin 32. There is an extension 33 on the idle lever 38, projecting below its fulcrum, and having a threaded boss to receive adjustin screw 34 that is maintained in position by lock-nut 35'." Asseem-the adjusting screw projects out of-the idle lever boss to engagewithasto flii. r

The throttle lever. 21 is not directly connected to the accelerator rod l5.- A lateral'pin 31 on throttle lever 21' pivotally mounts a swinging cam device'or arm '38 Which has its outer end engaged with a pin 39 on an internally threaded swivel block 4!] adf'ustably screwed upon the threaded end region Ila of accelerator rod i5. Cam arm 38 has an eccentric boss 4! at its fulcrum, said'boss arranged to engage a suitably shaped edge 42 on :one of the members of the U-shaped idle lever 30 against which this cam boss bears by reason of thegurgeof spring 21a and spring] 8.

When accelerator rod 15 is moved to the left (Fig. 2) by a depression of the throttle pedal l2, the cam arm 38 will swing counterclockwise on its pivot; 31 while the cam boss 4| engages the edge 42 of the idle lever 35-. Since the idle lever 30 is arrested at this time from moving clockwise by reason of the stop 36, the camming action of Fig. 2 while the U-shaped idle lever 30 remains static-nary. The effect of this camming action is that the spindle 26 is slowly rotated to open the butterfly valve 25 the proper distance for running the'engine at the desired slow speed to accomplish the initial coupling of the centrifugal clutch. As a result the engine will drive the vehicle through the clutch and transmission, at a creeping speed which is slow enough to permit the operator to park the car.

As will be seen, the throttle lever 21 is alongside this idlelever (Fig. 4) and the cam arm 38, or at least its cam boss 4|, is located between the members'of the U-shaped idle lever 30. In

normal or idling position, the .outer end. portion of cam arm 38 is engaged with a stop ear 43 at the end of an adjacent member of U-shaped idle lever 30, and at the end 'of the initial movement of the cam arm 38 a projection 44 of this cam arm will engage a sto 45 at the outer end of the second member of idle lever 30. These stops 43 and 45 limit the free swing of the cam arm 38 and they also predetermine, the amount of opening efiected by the butterfly valve 25 to initially couple the clutch for creeping movement of the vehicle. Further depression of the throttie pedal 12 will shift the accelerator rod [5 farther to the left, which, after cam arm 38 has engaged stop 45, will move the whole assembly (including the idle lever 30 and throttle lever 21) to the left for a full open position of butterfly valve 25. This will accelerate the engine speed for a complete coupling of the clutch.

It will be seen, when the operator depresses throttle pedal 12 a distance for the cam arm 38 to engage stop 45, such engagement will be sensed by him because thereafter further depression of the pedal will require more efio-rt to operate the assembly as a unit to move such unit to a position for driving the vehicle at a desired speed.

While this invention has been described in detail in its present preferred form or embodiment, it will be apparent to persons skilled in the art, after understanding the improvements, that various changes and modifications may be made therein without departing from the spirit or scope thereof. It is aimed in the appended claims to cover all such changes and modifications.

I claim:

1. In combination with a rockable spindle for a carburetor throttle valve and the like, a rocker armsecured to said spindle for oscillating the same; a manually reciprocable actuator rod; and control means operatively connecting said arm and actuator rod for effecting multiple-stage movement of said spindle, said control means comprising an idle lever swingingly mounted on said spindle; means arresting movement of said idle lever in one direction; and a cam device rotatably mounted on said rocker arm, said cam device having operative connection with said rod and being adapted to act on said idle lever when the latter is in said arrested position for efiecting movement of said arm independently of said idle lever to rock said spindle through a first stage of its movement; and continued movement of said cam device being effective to move said idle lever away from its arresting means and rock said spindle through another stage of movement.

2. In combination with a rockabie spindle for a carburetor throttle valve and the like, a rocker arm secured to said spindle for oscillating the same; a manually reciprocable actuator rod; and

5 control means operatively connecting said arm and actuator rod for effecting multiple-stage movement of said spindle, said control means comprising an idle lever swingingly mounted on said spindle, said idle lever having spaced members; means arresting movement of said idle lever in one direction; and a cam device operatively connected to and rotated by said rod, said cam device fulcrumed on'said rocker arm in engagement with a member of said idle lever and acting thereon when the idle lever is arrested for effecting movement of said rocker arm independently of said idle lever to rock said spindle through a primary stage of its movement, and the continued movement of said cam device being effective to engage it with another member of said idle lever for effecting bodily movement of said idle lever and the simultaneous movement of said rocker arm to rock said spindle through another stage of movement.

3. In combination with a rockable spindle for a carburetor throttle valve and the like, a control assembly for efiecting the rocking of said spindle in two stages, said assembly comprising a rocker arm secured ,to said spindle; a manually shiftable rod; a cam arm pivoted for limited swinging movement on said rocker arm; means operatively connecting said rod and said cam arm; an idle lever swingingly mounted on said spindle, said idle lever having spaced members positioned upon opposite sides of said cam arm whereby the aforesaid limited movement of the cam arm is effected by engagement of said cam arm with one and then the other of the respective idle lever members; a stop arresting movement of said idle lever in one direction; said cam device during its limited movement being adapted to act upon a member of said idle lever when the latter is arrested for effecting a first stage movement of said rocker arm independently of said idle lever, and a continued movement of said cam device acting to move said idle lever away from said arresting means and simultaneously therewith to efiect a second stage movement of said rocker arm to further rock said spindle.

4. A control assembly for an oscillatable spindle comprising a rocker arm secured to the spindle; a member swingingly mounted on the spindle independent of said arm; a fixed abutment efiective to arrest movement of said swinging member in one direction; a cam device rotatable on said rocker arm, said cam device being effective to act on said swinging member while in arrested position thereby to actuate said rocker arm and partially rock said spindle; and a manually operable rod connected to said cam device for rotating the latter.

5. A control comprising a rotatable spindle; a rocker arm secured to said spindle; an oscillatory idle lever swingingly carried by said spindle; a stop for arresting movement of said idle lever in one direction; an actuator device pivoted on said rocker arm and having operative connection with a manually reciprocated rod, whereby said actuator device is shifted on said rocker arm; and a cam operated by said actuator device, said cam being engaged with said idle lever and being efiective when said lever is arrested to move said rocker arm a predetermined distance independent of said idle lever.

6. A control as defined in claim 5 wherein the idle lever has a stop for limiting the predetermined independent movement of the rocker arm.

7. A control assembly for a rock spindle, comprising an arm secured to said spindle, said arm being movable to rock said spindle; an oscillatory idle lever movable on said spindle, said lever having a predetermined limit of movement in one direction; a cam device fulcrumed on said arm in engagement with said idle lever, said cam device being adapted for movement independent of said arm also with said arm, the said independent movement of said cam device being inefiective to move said idle lever from its arrested position but is efiective to initially move said arm to slowly rock said spindle a predetermined distance; and a reciprocable manually operable rod connected to and actuating said cam device.

8. A control assembly for a rock spindle, comprising an oscillatory arm secured to'said spindle for rocking the same; an oscillatory U-shaped idle lever movable on said spindle, said lever having arrested movement in one direction; a cam device swingingly carried by said arm for bodily movement therewith, said cam device being adapted during its swinging movement to successively engage with one member and then the other member of said U-shaped idle lever; and a longitudinally reciprocable manually operable rod connected to said cam device independent of said arm; said assembly. being so constructed and arranged that initial movement of said cam device effects a relatively slow swing of said arm while said lever is arrested whereby to slowly rock said spindle a portion of its rotation, and further movement of said cam device effects a. relatively rapid rocking of said spindle by a simultaneous movement of said arm and lever to complete the rotative movement of said spindle.

HAROLD NUTT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,397,987 Sheppy Nov. 22, 1921 

